Ludo-narrative dissonance is an odd phrase, isn't it?
It's a term invented solely to describe phenomenon in video games that can't happen in other media. This is when a game's mechanics or scope runs contrary to everything its story is trying to tell.
You might think that this isn't a big deal. If the story is good enough, it should survive the odd contradiction here or there, right? But a big part of video games is the immersion, even more so than books or films. People can forgive the occasional glitch, but something intentionally put in or allowed that contradicts the game's entire thesis? That's a lot harder to let go.
This can happen in a variety of large or small ways. It could be a level or scenario that contradicts what an earlier section was trying to say about the plot, theme, or characters. Or it could be something the game allows the player to get away with that the story would otherwise look down upon. It could be something as tiny as the set dressing or the clothes the characters are wearing.
Of all the ways games can contradict their own messages, these ten entries are the most egregious examples.
10. Eating Trash - Bioshock Infinite
Starting off with a rather small example, we have Bioshock Infinite. In many ways a game so fussed over until every detail runs like a Swiss watch, but alas the player cannot help but screw all that up, can they?
Mind you, it probably doesn't help for the game to set up main character Booker Dewitt as a badass, hard nosed private detective... and then have him eat half-chewed candy bars out of the trash. It's Bioshock tradition to make you scrounge for every bit of food and resource, but some stuff is just a little too disgusting for some characters.
Little details like that don't really pull you out of the experience, but they do leave you scratching your head why Booker, who HAS money for food and the mark that the city is looking for nice and covered up, would instead opt to just pull crap out of the waste bin and chow down on that instead of something actually cooked and ready to eat.